Defining variables using matrix entries

Hello, I have an equation with 200 variables and I want to assign them to a 1 column by 200 rows matrix. My variables are named ΔX_i where i goes from 0 to 100. My Matrix is named Matrix.

I have tried something like that:

ΔX_i := Matrix(i) but I get "Error, unsupported type of index, i"

Any ideas?

Thank you